1. Field of the Invention
This invention relates to a belt for transferring an in-production fibrous web, in particular a paper web or paperboard web, in a machine area of a machine producing the fibrous web, in particular a paper machine or paperboard machine, including at least one textile substrate and a coating, which is applied to the substrate and touches the in-production fibrous web, for obtaining a partial or complete impermeability of the belt.
Also, this invention relates to a machine, in particular a paper machine or paperboard machine, for producing a fibrous web, in particular a paper web or paperboard web, as well as to a use of a belt for transferring an in-production fibrous web, in particular a paper web or paperboard web, in one machine area or between two machine areas of a machine producing the fibrous web, in particular a paper machine or paperboard machine.
2. Description of the Related Art
Such a belt for transferring an in-production fibrous web in a machine area of a machine producing the fibrous web is already known from a multiplicity of publications. The two publications EP 0 576 115 B1 (DE 693 02 136 T2) and U.S. Pat. No. 6,605,188 B2 can be cited purely by way of example.
The belt should generally guarantee stable running of the in-production fibrous web through the machine. This is important in particular in the machine areas in which the in-production fibrous web is not guided by a roller or a belt such as a mesh belt, a press felt or a dryer fabric.
The known belts all have different properties, in particular in the region of their surfaces facing the in-production fibrous web. From the previously mentioned publication EP 0 576 115 B1, for example, there is known a surface which comes into contact with the web and has a degree of roughness that reacts to and recovers from pressure. By contrast, the also mentioned publication U.S. Pat. No. 6,605,188 B2 discloses a belt which is includes of a basic structure and a surface layer touching the in-production fibrous web. In this case the surface layer includes at least two types of fiber with different properties such as hydrophilic versus hydrophobic for example. Other different properties can also be the polarities, the hydrophilic properties, the electric charges, the surface tensions, the coefficients of friction, the degrees of fineness or the porosities.
The different properties of the belts disclosed in the publications mentioned always refer to their overall areas, meaning across the overall widths of the belts in question. Hence it is not possible to make sufficient allowance for different transverse profiles of the respective fibrous web during production, with the result that a compromise involving quality losses and waste quotas must always be accepted.
Furthermore, the publication U.S. Pat. No. 6,770,172 B2 discloses an endless press felt which includes of one basic fabric and at least one fleece layer that has in its two edge regions a different structure respectively than in the middle region. However, the corresponding structure with respect to the regional area is the same in the various regions. In other words, this means that the respective regional area has a non-differencing characteristic. On the whole this embodiment results, among other things, in an improved guidance of the material web through the press nip.
What is needed in the art is a belt of the type initially referred to such that different transverse profiles of the fibrous web can be better compensated during its production. Also, a corresponding machine and a corresponding use are to be disclosed.